Wireless telephones, such as mobile/cellular telephones, cordless telephones, and other consumer audio devices, such as mp3 players, are in widespread use. Performance of such devices with respect to intelligibility can be improved by providing noise cancelling using a microphone to measure ambient acoustic events and then using signal processing to insert an antinoise signal into the output of the device to cancel the ambient acoustic events.
While many audio systems implemented for personal audio devices rely on a single output transducer, in the case of transducers mounted on the housing of a wireless telephone, or a pair of transducers when earspeakers are used or when a wireless telephone or other device employs stereo speakers, for high quality audio reproduction, it may be desirable to provide separate transducers for high and low frequencies, as in high quality earspeakers. However, when implementing active noise cancellation (ANC) in traditional systems, crossover filters present in an earspeaker housing may be present in the antinoise path, and thus may introduce latencies in the antinoise path, which may reduce the effectiveness of the ANC system.
Accordingly, it may be desirable to provide for a multiple transducer driver system that minimizes or reduces such latencies.